They were playing ring-around-a-Rosie today in Boston. Roise Ruiz, 26, an administrative assistant for a New York City metal trading firm, was crowned the women's winner of the Boston marathon Monday.

But after the race, some runners began to wonder whether Ruiz deserved the traditional laurels for her performance on the roads or for her acting out the final stages of the world's most famous marathon.

Jacqueline Gareau of Montreal, who finished second, and Patti Lyons of West Roxbury, Mass., third, said they had not see Ruiz during the race.

Will Cloney, the marathon director, said he had no proof either way and might never have, but announced that he would begin an investigation to try to determine "whether there was a discrepancy," and, if necessary, would "adjust places accordingly."

Ruiz and her coach, appearing on a local television show today, said she ran every step of the 26-mile 385-yard course from suburban Hopkinton to the towering Prudential Center in Boston's downtown retail district.

"I don't know what happened," Ruiz said in a "Good Day Show" interview. "I had no idea I was first. I'm happy for myself. This is a big accomplishment for me. I'm sad such controversy is going on. I really don't know why. I ran the race. I would not say anything different.

"I'm upset. I've been crying a lot, but it's not up to me to clear myself because I ran the race.

"In spite of everything, I'm glad I came," said the 26-year-old Havana-born runner who immigrated to Florida in 1961.

Ruiz's coach, Steve Marek of Suburban Road Runner Club, said, "we have witnesses to prove that she was at the start."

Reached today at his home in Scituate, Cloney said, "We've had numerous calls, none of them definitive, pro as well as con, from people who saw her at various places.

"With 5,000 people running, and 1 1/2 million people watching, and 600 media people looking for a story, somebody somewhere, somehow should have seen her. We hope to get some proof somewhere."

Cloney said three members of a local broadcasting team focusing on the women's race had reviewed "three sets of raw tapes" and "they swear that nowhere did they see this woman."

Cloney said he also had asked Boston Globe writer Joe Concannon to review the tapes and that Concannon did not see Ruiz. Cloney said he would take affidavits from persons who had seen the tapes, as well as course officials and runners that finished around her, but did not expect a decision for at least a week."

Asked what he thought the chances were of reaching a definitive decision, Cloney replied, "Fifty-fifty."

Asked what he would consider definitive proof, he said, "A statement from a runner at Wellesley, for example, saying he passed this person and then there she was again in front of him. But still, it would be just her word against his."

Two runners who finished near Ruiz said today they had not seen her on the course. Dominic Friscino of nearby Alston, who finished 12 seconds ahead of Ruiz, said, "I never saw her, I never knew she was there. Last year, I finished a couple of seconds ahead of (winner) Joan Benoit. I knew she was there from the groundswells of noise as she went by. There was no such noise this year."

Asked if he normally would be aware of a runner 12 seconds behind him, Friscino said, "I was aware of Benoit last year and she was farther behind. I could tell when she (Benoit) was getting close because the crowd goes nuts when they spot the first woman."

Friscino said he became skeptical when he heard that Ruiz was training only 60 miles a week and when he saw her after the race.

"She didn't look like she had run 26 miles," he said. "Her shirt was sweat-stained but it should have been soaked. She should have had some salt stains from having dried. But she didn't even have those. I don't believe it."

Ruiz crossed the finish line 2 hours 31 minutes 56 seconds after the race began, which would make hers the third fastest women's marathon ever run.

Bennett Beach of Larchmont, N.Y., who finished 19 seconds after Ruiz, said, "If it hadn't been for the heat, maybe I would believe it. But too many things are fishy."

Beach said his first reaction when he crossed the finish line was, "At least I beat the first woman."

"I don't want to sound sexist, but I'm a slow starter and generally not too many people pass me," Beach said. "If someone does, I take a pretty good look. I have no recollection of a shirt that says Metals Traders, Inc.

"One thing baffles me," he continued. "My wife was standing at 24 1/2 miles at Kenmore Square. She saw Rodgers and she saw me and no woman came through. I can't believe she wouldn't have seen the red W50 (Ruiz's number)."

All the evidence so far is circumstancial: not seeing someone is not proof that she was not there. Many runners are skeptical that Ruiz could have run so well in only her second marathon. But Grete Waitz, the world record holder, has run only two marathons and set world records in both. She is also an established runner at other distances.

Other runners were skeptical that Ruiz could take 25 minutes off her previous marathon time of 2:56.31, recorded in last year's New York marathon, especially in Monday's near-80 degree heat.

Asking how it was possible to improve so much, Ruiz said, "How is it possible to run 2:56 in your first marathon, considering that I had had knee surgery, and had not trained very well."

Today, Fred Lebow, director of the New York marathon, said he was reviewing the 1979 race.